Portable Stove and Slow Cooker

ABSTRACT

A multi-function, portable, electrically-heated appliance for use in vehicles such as automobiles, trucks, recreational vehicles, watercraft and aircraft. A unit with digital controls can be powered through connection to a vehicle DC power outlet such as a cigarette lighter, as well as other external power sources. A heating element transfers heat energy to a removable container housed within the base unit to heat foods or liquids. The removable container is sealed by a cover so the food or liquids may be cooked or kept warm.

RELATED UNITED STATES APPLICATION DATA

This application claims priority benefit from U.S. Provisional Application No. 61/303,381, filed on Feb. 11, 2010.

BACKGROUND

Freight transportation is a critical component of global business. In fact, it is the backbone of numerous industries and companies. Trucks are the product delivery lifeline between producers and consumers; they move food, fuel, and all of the goods that keep the world economy going. With very few exceptions, literally every manufactured product is hauled on a truck at some point in its ultimate journey to the consumer.

Long-haul truckers receive their income based on various models. Drivers may be paid a fee, for example, based on any of the following: hourly wage, miles driven, size or weight of load carried, number of stops along the delivery route, or the number of pieces delivered/unloaded. There may be other measures of payment as well.

Due to the high demands of the job, drivers are known to work for months at a time without days off. Some even prefer to forgo a traditional home, and take up permanent residence in their truck, usually with a large and well-equipped sleeper berth. Long-haul company drivers typically earn as little as one day off for every week of work.

As a result, truckers are incentivized to maximize their income by spending as much time on the road as possible. While some trucks are equipped with on-board sleeping and cooking facilities, most are not. This means that truckers have to stop to eat, which may slow them down and reduce their income. In addition, it is not easy to eat healthily at typical truck stops and fast-food restaurants on the road. For all of these reasons, truckers will find tremendous utility in a portable stove that is accessible during their travels so that they can heat or cook a healthy meal of their own choosing. It is desirable that such a stove be small enough to fit between the front seats of their truck so it can be used while they are traveling. It should also be light, simple to use, easy to clean, and small enough for easy stowage in the truck cab. A flexible design should allow for heating and cooking of solid foods or liquid-based foods such as soups or stews.

Others who spend long periods of time traveling in automobiles, vans, recreational vehicles, watercraft and aircraft face the same issues as truckers in terms of desiring a way to heat and/or cook food while traveling in a vehicle. Obviously, the use of an open flame, as would be the case with a gas stove is hazardous while the vehicle is moving. Also, it will be understood that no easily connectible outside power source is available so appliances requiring more permanent electrical outlets or campsite hookups cannot be used while the vehicle is moving. As a result, portable heating devices capable of use while a vehicle is in motion have typically been limited to devices such as baby bottle warmers or coffee mug warmers and the like which have limited applicability for food heating and cooking for the general population.

The present invention overcomes the above-mentioned limitations by providing for a lightweight, compact, portable, digitally controlled electric stove for use in food preparation in a variety of vehicles while on the move, or at other locations where traditional appliance connections are unavailable. The present invention makes heating and cooking food a practical option whether the vehicle is moving or stationery. It should be understood that the present invention may also be useful in places with traditional AC power sources including homes, hotels and motels, offices, or other locations where a simple to use and portable stove is convenient. Powering the portable stove in such places may be accomplished by using a DC to AC converter or by producing the portable stove with dual power circuits for using DC or AC depending on the type of power available in a given location.

BRIEF DESCRIPTION OF THE DRAWINGS

For a better understanding of the present invention, and to show more clearly how it functions, reference will now be made, by way of example, to the accompanying drawings. The drawings show preferred embodiments of the present invention in which:

FIG. 1 is a perspective view of the portable stove;

FIG. 2 is a perspective exploded view of the portable stove showing the individual components of the stove;

FIG. 3 is a perspective view of the a portable stove with the cover open and the warming tray in place;

FIGS. 4A-4B are perspective views of a removable tray in warming and steaming embodiments of the portable stove;

FIG. 5A-5B are perspective views of the cooking pan of the portable stove with and without the lid;

FIG. 6 is a top view of the cooking pan of the portable stove;

FIG. 7 is a perspective view of the portable stove with the top, cooking pan and trays removed;

FIG. 8 is a perspective view of the underside of the heating pan assembly of the portable stove;

FIG. 9 is a perspective view of the underside of the cover of the portable stove;

FIG. 10 is a front view of the portable stove;

FIG. 11 is a view of the electronic display used in the portable stove; and

FIG. 12 is a block diagram of the circuit of electrical components used in the portable stove.

DETAILED DESCRIPTION OF THE INVENTION

The present invention will now be described more fully with reference to the accompanying drawings. It should be understood that the invention may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein.

As shown in FIGS. 1-12, a lightweight, compact, fully self-contained and portable stove system is used for the purposes of food preparation including but not limited to cooking, heating and/or simmering.

FIG. 1 illustrates a perspective assembly view of a stove unit 101 which is a multi-function appliance that works as a stove, oven or slow cooker. Stove unit 101 warms, re-heats and/or cooks liquids and raw or thawed food quickly (similar to standard household cooking appliances) while comprising a compact, lightweight and self-contained unit. Average inside temperature can reach 350° F. in less than 30 minutes with an operating range of approximately 100° F. to 350° F. In one embodiment, the dimensions of portable stove 101 are approximately 11.75 inches long by 8.5 inches wide by 7.87 inches high and stove 101 weighs approximately 4.5 pounds.

FIG. 2 is an exploded assembly view of stove unit 101 showing the major component parts. Stove unit 101 is formed of a bottom cover 201 with feet 203 on the underside and a frame rim 205 for engaging stove body 207. Stove body includes a recessed section that forms the area in which a heating pan 209 is seated. Within heating pan 209 is nestled cooking pan 211 which has handles or handholds 213 on opposing sides for lifting cooking pan 211. Warming or steaming tray 215 may be used as an insert inside of cooking pan 211 to warm or steam food. A lid 217 can be used to cover cooking pan 211 either with or without warming tray or steaming tray 215 depending on how stove 101 is being used.

A swiveling handle 219 is affixed to stove body 207 in a hole 221 on either side of stove body 207. A power cord 223 with a lighter adapter 225 is plugged into a standard automobile lighter (not shown) to provide DC power to stove unit 101.

A cover 227 is used to seal the top of stove unit 101 to retain heat inside of cooking pan 211 during operation. Cover 227 is formed of outer cover 229 and inner cover 231 with a seal ring 233 mounted to the surface of inner cover 231 facing cooking pan 211.

On the front of stove unit 101 is a digital display 235 for providing information to the user. The display also includes a set of buttons and LED indicators allowing the user to operate stove 101. A heating element 237 controlled by buttons on display 235 is affixed to the bottom of heating pan 209. Finally, a latch release 239 is situated above display 235 for unlatching cover 227.

FIG. 3 is a perspective view of portable stove 101 with cover 227 open and steaming tray 215 in place. Steaming tray 215 holds food that is steamed by heated water rising up from cooking pan 21 below it. Steaming tray 215 is preferably constructed of a durable material, such as aluminum, with a non-stick coating applied to all tray surfaces to enable easy cleaning and minimize the need for cooking oils or other additives. Aluminum material is preferable, as it is an excellent conductor of heat as well as being lightweight and durable. Stove unit 101 is powered by a power cord 33 located at the rear of stove unit 11. Power cord 33 has a lighter adapter 225, the end which is plugged into a standard lighter outlet in a vehicle (e.g. automobiles, trucks, recreational vehicles, watercraft or aircraft) that provides for continuous 150 watt 12 volt direct current (12VDC) output. Additionally, stove unit 101 may be powered by other 12VDC compatible supply sources providing continuous 150 watt 12VDC output or similar output.

FIGS. 4A and 4B are perspective views of a removable tray 215 in two different embodiments. FIG. 4A shows a first type of removable tray 215 for warming food as well as for preparing smaller portions of cooked foods or liquids. Tray 215 sits inside cooking pan 211. FIG. 4B shows an alternative design for steaming foods using heated water in cooking pan 211. Steaming tray 215 is made with holes 401 to permit a steaming operation inside of stove 101 when water placed in cooking pan 211 is heated and converted to steam that rises through holes 401 to steam food placed in steaming tray 215. Removable tray 215 is approximately 5.8 inches square by 1.375 inches deep.

FIG. 5A-5B are perspective views of cooking pan 211 of portable stove 101 with and without lid 217. FIG. 5A shows cooking pan 211 enclosed with cooking pan lid 217 which incorporates cooking pan lid handle 501. Cooking pan lid 217 acts as a removable cover to contain cooked foods or liquids within cooking pan 211 when it is removed from stove unit 101, preventing spillage and keeping the food or liquids at a heated temperature for an extended period of time. FIG. 5B is a view of cooking pan 211 without lid 217 and showing handholds 219 for grasping cooking pan 211.

Removable cooking pan 211 is preferably constructed of a durable material, such as aluminum, with a non-stick coating applied to all pan surfaces to enable easy cleaning and to minimize the need for cooking oils or other additives. The aluminum material is preferable as it is an excellent conductor of heat while being light and durable. Alternatively, clad cooking pan 211, may be made of materials sandwiching a thick layer of aluminum or copper between two sheets of stainless steel. Cooking pan 211 functions both as a cooking container and serving dish and preferably holds at least 1.5 liters in one embodiment with cooking pan 211 having approximate dimensions of 6.25 inches long by 6 inches wide by 4 inches deep. The configuration of stove unit 101 is intended to provide dimensions that allow it to fit comfortably between the seats of a truck or other vehicle while being lightweight and easy to stow. However, it should be understood that stove unit 101 can be made larger or smaller so that cooking pan 211 is, in turn, larger or smaller than the 1.5 liter capacity described in this embodiment.

Cooking pan 211 incorporates handles or handholds 219 with a heat-resistant rubber coating to protect the user from burns.

FIG. 6 is a top view of cooking pan 211 of portable stove 101 with handles 219 and the transparent outline of heating element 237. Heating element 237 is affixed to heating pan 209 in which cooking pan 211 is nestled during use.

FIG. 7 is a perspective view of portable stove unit 101 with cover 227 and cooking pan 211 removed. Stove unit 101 houses operation display 235 and latch release 239. In addition, stove unit 101 has bottom cover 201 which is preferably manufactured using a molded plastic material such as polypropylene. Bottom cover 201 preferably incorporates four feet 203 (not shown in FIG. 7) to allow the unit to sit stably on a flat surface. Stove unit pivot assembly 701 provides a pivot point 703 for cover 227 to open and close. In addition, stove unit pivot assembly 701 incorporates a stop for top cover 227 to maintain top cover 227 in the open position. Latch release 239 secures cover 227 in the closed position and releases cover 227 to enable access to cooking pan 211. Handle 219 pivots on handle mounts 705 to allow a user to rotate handle 219 to the up position for carrying stove unit 101 or to rotate handle 219 to the down position to allow for access to cover 227 while stove unit 101 is in use.

Heating element 237 converts vehicle electrical current to heat energy to enable heating of cooking pan 211. Heating element 237 may be, for example, a 12 volt DC 150 watt common copper heat tube element. Removable cooking pan 211 nestles within heating pan 209 to ensure full contact with heating element 237. Spring cap 707 is attached to the top of a spring (see FIG. 8) that pushes up against cover 227 so that when cover 227 is opened, cooking pan 211 is raised above the rim of heating pan 209 allowing for easy removal of cooking pan 211 by the user. Spring cap 707 is made of aluminum or another heat conducting metal.

FIG. 8 is a perspective view of the underside of heating pan 209. Heating element 237 is attached to the underside of heating pan 209 allowing for the transfer of heat energy from heating element 237 to the underside of heating pan 209 which is, in turn, transferred to cooking pan 211 nestled inside heating pan 209. Spring cap 707 which is on the inside of heating pan 209 attaches to spring 801 that passes through a hollow space at the center of heating element 209 and is mounted to heating pan 209 by spring mount 803. Spring 801 is mounted to the base of stove unit 101 at its other end and it functions to cushion cooking pan 211 as it nestles inside of heating pan 209. Spring 801 also raises cooking pan 211 above the rim of heating pan 209 when top cover 227 is opened and the user has access to cooking pan 211 (or warming or steaming tray 215). The combination of spring 801 with spring cap 707 includes a temperature detector to sense the temperature of the outside bottom surface of cooking pan 211 where spring cap 707 contacts cooking pan 211. Where spring 801 is mounted to the base of stove unit 101 it is attached to a circuit for displaying the temperature sensed at spring cap 707 and that controls the other operations of stove unit 101. The circuit is shown in FIG. 12.

FIG. 9 is a perspective view of the underside of cover 227 of portable stove 101. Cover pivot assembly 901 engages stove unit pivot assembly 701 for attaching cover 227 to stove unit 101. Cover 227 is made up of four major components: (a) outer cover 229; (b) inner cover 231; (c) seal ring 233; and (d) metal cover 903. Outer cover 229 and inner cover 231 are preferably manufactured of a plastic molded material such as polypropylene. Metal cover 903 forms part of inner cover 231 and provides a durable heat-resistant surface and functions as a lid to cooking pan 211. Metal cover 903 is preferably constructed of aluminum and provides centrally located vent holes 905 to allow pressure from the heat and cooking process to be vented from stove unit 101 through cover 227 to the outside. Seal ring 233 seals cover 227 to the top of cooking pan 211 to prevent loss of heat and pressure. Preferably, seal ring 233 is molded of a high-temperature silicone rubber material to withstand the high temperatures reached in stove unit 101 and to keep generated heat, as well as any liquid inside of cooking pan 211.

FIG. 10 shows a front view of portable stove 101 which preferably is molded of a plastic material such as polypropylene. When a user activates latch release 239, cover 227 is disengaged and pivots upward and out of the way to allow access to the inside recessed area of portable stove 101 which houses heating pan 209, cooking pan 211 and/or warming tray 215. Latch release 239 may work by a spring loaded push button (not shown) for releasing cover 227 or by alternative means such as a sliding latch mechanism, etc. Display panel 235 provides digitally-adjustable heating controls and temperature or other readouts on a LCD, LED or other type of digital display. Display panel 235 comprises a set of flexible touch pad switches, light indicators and display, and is mounted in stove unit 101. The touch pad switches generate contact signals in response to the following user operations: (a) on-off switch 1001; (b) plus temperature switch 1003; (c) minus temperature switch 1005; and (d) mode switch 1007. Display 235 shows the internal temperature of cooking pan 211 in degrees Fahrenheit (or Celsius if desired) and also the 12VDC power consumption in watts when power is being supplied to stove unit 101. Additionally, display 235 indicates whether stove unit 101 is in power mode or temperature mode. A light indicator 1009 indicates whether the power is on. A control circuit attached to but separate from display 235 controls heating element 237 and the power in response to user input at the switches on display 235. The control circuit is shown in detail in FIG. 12.

FIG. 11 is an alternative display panel 235 for operating stove unit 101 and providing information to the user, with: (a) on-off switch 1001; (b) up arrow key for raising temperature 1003; (c) down arrow key for lowering temperature 1005; and (d) function switch 1007. Each of these switches performs the same functions as the switches described above with the same reference numerals in FIG. 10. A pair of indicator lights 1101 and 1103 for heat and temperature respectively, indicate which mode the portable stove unit is currently in. For heat mode, full power is applied and the stove heats to the highest temperature possible. While in heat mode, the actual temperature inside of cooking pan 211 is displayed as measured at temperature detector affixed to spring cap 707. In temperature mode, the user can select a desired heating temperature and once that temperature is reached inside cooking pan 211, the desired temperature is maintained. Display 235 shows the internal temperature of cooking pan 211 in degrees Fahrenheit (or Celsius if desired).

Referring to FIG. 10 and FIG. 11, on/off switch 1001 is electrically coupled to an indicator light 1009 to signal the operating state of the stove unit (“on” or “off”). Mode or function switch 1007 provides for dual-function heating control. The default “power mode” setting provides for maximum fixed wattage causing the interior of cooking pan 211 to reach approximately 350° F. in less than 30 minutes. Power mode capability is controlled by on/off switch 1001 or until the user switches to temperature mode.

In temperature mode, function switch 1007 provides for a number of individual heat settings. A typical range of operation for the portable stove is between 100° F. and 350° F. in 25° F. increments. It should be understood that 25 degree increments are customary for stoves and are convenient for users. However, the adjustment increments could be made larger or smaller during manufacture of the product to meet the particular needs of the manufacturer or the user. The temperature range may also be increased to a higher top temperature. Additionally, mode switch 45 provides for a “keep warm” function by using one of the three lower pre-defined temperature settings (100° F., 125° F. or 175° F.) to keep food or liquids warm. Other preset values may be substituted at the time of manufacture. Once set to a pre-defined temperature, stove unit 101 will automatically maintain the temperature setting. Stove unit 101 will automatically adjust and maintain the temperature of cooking pan 211 for the desired heat setting between 100° F. to 350° F. User activation of the plus temperature switch 1003 or the minus temperature switch 1005 adjusts the temperature setting up or down respectively. The default temperature setting when stove unit 101 is powered on is 200° F., but the stove designer may substitute another default temperature for power on.

Once stove unit 101 reaches a desired temperature, display 235 displays the setting for a brief period of time, 5 seconds for example, and then locks-in that temperature and maintains the temperature until the user changes the setting. Cooking pan 211 temperature is displayed on display 235 and adjusts accordingly depending on temperature changes within cooking pan 211.

FIG. 12 is block diagram of the circuit with electrical components used to power and direct operation of stove unit 101. A central processing unit or CPU 1203 directs control of all functions on stove 101. Power is delivered to CPU 1203 through lighter adapter 225 plugged into a vehicle lighter outlet. Alternatively, power may be supplied by a standard wall plug (not shown). Power is directed through power input 1205 and is transformed by power transformer 1207 before being input to CPU 1203. Power is also provided directly through on/off switch 1001 to heating element 237. Power indicator 1009 is connected to power input 1203 for indicating to a user when power is being supplied to stove unit 101.

CPU 1203 receives input from temperature detector 1209 that senses the temperature at the outside bottom surface of cooking pan 211 where spring cap 707 contacts cooking pan 211 on the outside bottom surface and spring 801 is mounted to the base of stove unit 101. A signal is provided to CPU 1203 for displaying the temperature sensed at spring cap 707 on digital display 235. Keypad switches 1211 include plus temperature switch 1003, minus temperature switch 1005 and mode switch 1007. When a user depresses switches 1211, a corresponding signal is sent to CPU 1203 to cause CPU 1203 to control heating element 237 and display information on digital display 235. CPU 1203 also causes heat indicator light 1101 and temperature indicator light 1103 to be illuminated when appropriate.

Protection for circuit 1201 is provided through the use of an automotive fuse that is typically rated at 20 amps and 250V. The fuse (not shown) may be incorporated inside of lighter adapter 225 for easy replacement. Stove unit 101 may be configured to provide for automatic shut-off whenever cooking pan 211 is removed for cleaning or serving to prevent overheating and ensure safety. The automatic shut-off function is effected by a spring sensor and spring cap 57 assembly that senses the position of spring cap 57.

While the invention has been described with respect to the figures, it will be appreciated that many modifications and changes may be made by those skilled in the art without departing from the spirit of the invention. 

1. A portable stove comprising: a compact, lightweight, self-contained stove unit including a recessed area; a stove cover that fits over an opening above the recessed area to seal in heat; a heating element situated within the recessed area for providing heat; a heating pan positioned in close proximity to the heating element that fits within the recessed area and conducts heat from the heating element to the recessed area; a cooking pan removably fitted within the heating pan with an outside surface of the cooking pan contacting an inside surface of the heating pan; a circuit for delivering power to the stove from a power source, the circuit including; a control panel affixed to an outside surface of the stove unit for displaying current temperature, current temperature setting and power status; and a switch for adjusting the temperature setting.
 2. The portable stove of claim 1 wherein the power source may be either: (a) DC; or (b) AC.
 3. The portable stove of claim 1 wherein the temperature may be incrementally adjusted upwards or downwards.
 4. The portable stove of claim 1 wherein a top rim of the cooking pan is nested within with the top rim of the heating pan so that the stove cover seals over a top opening of the cooking pan
 5. The portable stove of claim 3 wherein the cooking pan can be removed from the stove unit.
 6. The portable stove of claim 5 wherein the cooking pan includes heat resistant handles integrated with the rim of the cooking pan.
 7. The portable stove of claim 1 further comprising a tray that nests within the cooking pan.
 8. The stove of claim 7 wherein the tray is made of solid material;
 9. The stove of claim 7 wherein the tray includes holes in a base of the tray to permit steam to rise through the base.
 10. The stove of claim 1 further comprising a heat conducting insert formed in a bottom of the cover that forms a lid over the heating pan when the cover is in a closed position.
 11. The stove of claim 1 further comprising a seal in a bottom of the cover that fits around the periphery of an opening of the cooking pan.
 12. A portable stove comprising: a compact, lightweight, self-contained stove unit including a recessed area; a stove cover that fits over the recessed area; a heating element situated within the recessed area; a cooking pan that fits in the recessed area and that is in conductive contact with the heating element; a circuit for delivering power to the stove from a power source; a display affixed to the stove unit for displaying temperature; and a switch for adjusting temperature.
 13. The portable stove of claim 12 wherein the power source may be either: (a) DC; or (b) AC.
 14. The portable stove of claim 12 wherein the temperature may be incrementally adjusted upwards or downwards.
 15. The portable stove of claim 12 wherein the cooking pan can be removed from the stove unit.
 16. The portable stove of claim 12 wherein the cooking pan includes heat resistant handles.
 17. The portable stove of claim 12 further comprising a tray that nests within the cooking pan.
 18. The stove of claim 17 wherein the tray is made of solid material;
 19. The stove of claim 17 wherein the tray includes holes in a base of the tray to permit steam to rise through the base.
 20. The stove of claim 12 further comprising a heat conducting insert formed in a bottom of the cover that forms a lid over the cooking pan when the cover is in a closed position.
 21. The stove of claim 12 further comprising a seal in a bottom of the cover that fits around the periphery of an opening of the cooking pan. 